- leilei: Well, I have two people who claim they experience this slowdown. Maybe it only happens on some host CPU's? Because from what I know, I don't experience any myself, either, but they swear they do.

And I am one of them. Some DOS programs shows abnormal low performance drops (15-30% with P200) with any pentium cpu selected in actual PCem builds. I've tried Dreams to Reality and Pyl (Dust) with the PCem from 18.07.2017 (commit 16a453b). Performance stutters most noticeable at a game launch. Also in Pyl this could be easily observed anytime you bring the main menu from the game. Status window shows the drop in Real speed MIPS, but effective clock remains stable. There is no such issue with the public PCem v12 release. My host config is Intel Core i5-2500K, 16GB RAM, Nvidia GeForce GTX 780Ti, Win 10 x64.

- leilei: That has nothing to do with it... the first person that reported the bug was given a binary compiled by me on around March, with no -flto or anything, and it was at 100%. A build from around June, compiled with the exact same flags, has the slowdown. SA1988 had the same result, and he even pinpointed the exact commit that introduced it.
Maybe the fact you use -flto masks the problem. Try compiling a non-flto build and running it.

Didn't try Derby (couldn't reproduce it earlier) but that last commit did fix up some other recompiler chokers:
Jagged Alliance
Red Alert
One Must Fall 2097
Puyo Puyo 2
STTNG A Final Unity
Warcraft II
(and probably a lot more that choked Pcem's recompiler at a static screen or miles sound systems)

Does this same commit improve the issue of the recompiler choking at the Windows desktop, DOS prompt, etc.? Can't compile the latest version to check at the moment, but I'm curious. If so, that's a huge step forward!

SarahWalker wrote:I was never able to reproduce this issue, but rev 932 addresses what I _think_ the bug was. TheMadLynx, if you're still around, could you try this commit?

I've tried Pyl with 9b72b24 commit. It is not perfect but definitely a huge improvement. Game gets into main menu almost instantly, like on real hardware. Gameplay is smooth enough, like on real hardware too. But there is still odd slowdown in the main menu opened when the game is running. Nevertheless, it is a lot faster than the previous build I've tried.